This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, IPv4 addressing and packet format, fragmentation, and IPv6 advantages over IPv4 such as a larger address space and better header format. Key aspects of IPv4 include the header length field, total length field, identification field for fragmentation, flags, fragmentation offset, checksum, and protocol field. IPv6 improvements include a fixed header length, larger addresses, priority and flow label fields, and extension headers.
Guided transmission media uses cabling to bind data signals, also known as bound media. Types include open wire, twisted pair, coaxial cable, and optical fiber. Unguided media transmits signals as electromagnetic waves via radio waves, microwaves, or infrared light. It can propagate through the ground, sky, or line-of-sight. The electromagnetic spectrum is divided into bands like VLF, LF, MF, HF, VHF, UHF, SHF, and EHF that determine the propagation method and applications.
1. SONET/SDH is a standard for transmitting digital signals over optical fiber. It uses synchronous multiplexing to combine lower-speed signals into higher-speed signals for transmission.
2. The basic building blocks of SONET/SDH infrastructure are terminal multiplexers, add/drop multiplexers, and digital cross-connects. Terminal multiplexers combine signals, add/drop multiplexers can remove and insert signals, and cross-connects route signals between rings.
3. SONET/SDH uses rings and path protection to provide self-healing networks. Rings allow signals to be rerouted if a fiber is cut. Path protection transmits redundant
HiperLAN was developed as a wireless local area network standard by ETSI to provide higher data rates than early 802.11 standards. HiperLAN Type 1 achieved data rates up to 2 Mbps for ad hoc networking. HiperLAN Type 2 was later developed to provide connection-oriented service up to 54 Mbps, with quality of service guarantees, security, and flexibility. It uses OFDM in the 5 GHz spectrum for robust transmission. While early products only achieved 25 Mbps, the standard provides a framework for higher speeds as technologies advance. HiperLAN is intended to complement wired networks by providing wireless connectivity in hotspot areas like offices, homes, and public places.
This document discusses IPv4 and IPv6 addressing and routing. It covers topics such as:
- IPv4 addresses are 32-bit and unique, while IPv6 addresses are 128-bit
- Classful and classless addressing in IPv4, including network masks
- Network address translation (NAT) allows private addresses to connect to the public internet
- Routing protocols like RIP, OSPF, and BGP are used for intradomain and interdomain routing based on metrics and shortest paths
- IPv6 was developed to address the long-term address depletion problem in IPv4
The document is a paper on the network layer written by Muhammad Adil Raja. It begins with an introduction that defines the key functions of the network layer, including getting packets from source to destination across multiple hops. It then outlines the topics to be covered, which are network layer design issues, routing algorithms, congestion control algorithms, and references. The body of the document discusses these topics in more detail through several sections. It covers issues like whether the network layer should provide connection-oriented or connectionless service, and compares virtual circuit and datagram networks. It also examines routing algorithms and the optimality principle.
E1 LINK IS EUROPEAN FORMAT ,Europe Line Rate
,E1 LINK, E1 VS T1 LINK, E1 SPECIFICATION, E1 ENCODING tECHNIQUES, high density bipolar , alternate marking inversion,itut,t1,e1 frame format
Slide 02 - Asynchronous Transfer Mode (ATM).pdfKingsleyTettey
This document provides an overview of Asynchronous Transfer Mode (ATM). It discusses how ATM was developed to allow telephone networks to carry different types of traffic beyond just voice calls. The key aspects of ATM covered include its cell-based format and connection-oriented design. Quality of service is handled through permanent and switched virtual connections. While ATM provided capabilities for multimedia networking, its complexity and costs prevented it from widespread adoption compared to other technologies.
Guided transmission media uses cabling to bind data signals, also known as bound media. Types include open wire, twisted pair, coaxial cable, and optical fiber. Unguided media transmits signals as electromagnetic waves via radio waves, microwaves, or infrared light. It can propagate through the ground, sky, or line-of-sight. The electromagnetic spectrum is divided into bands like VLF, LF, MF, HF, VHF, UHF, SHF, and EHF that determine the propagation method and applications.
1. SONET/SDH is a standard for transmitting digital signals over optical fiber. It uses synchronous multiplexing to combine lower-speed signals into higher-speed signals for transmission.
2. The basic building blocks of SONET/SDH infrastructure are terminal multiplexers, add/drop multiplexers, and digital cross-connects. Terminal multiplexers combine signals, add/drop multiplexers can remove and insert signals, and cross-connects route signals between rings.
3. SONET/SDH uses rings and path protection to provide self-healing networks. Rings allow signals to be rerouted if a fiber is cut. Path protection transmits redundant
HiperLAN was developed as a wireless local area network standard by ETSI to provide higher data rates than early 802.11 standards. HiperLAN Type 1 achieved data rates up to 2 Mbps for ad hoc networking. HiperLAN Type 2 was later developed to provide connection-oriented service up to 54 Mbps, with quality of service guarantees, security, and flexibility. It uses OFDM in the 5 GHz spectrum for robust transmission. While early products only achieved 25 Mbps, the standard provides a framework for higher speeds as technologies advance. HiperLAN is intended to complement wired networks by providing wireless connectivity in hotspot areas like offices, homes, and public places.
This document discusses IPv4 and IPv6 addressing and routing. It covers topics such as:
- IPv4 addresses are 32-bit and unique, while IPv6 addresses are 128-bit
- Classful and classless addressing in IPv4, including network masks
- Network address translation (NAT) allows private addresses to connect to the public internet
- Routing protocols like RIP, OSPF, and BGP are used for intradomain and interdomain routing based on metrics and shortest paths
- IPv6 was developed to address the long-term address depletion problem in IPv4
The document is a paper on the network layer written by Muhammad Adil Raja. It begins with an introduction that defines the key functions of the network layer, including getting packets from source to destination across multiple hops. It then outlines the topics to be covered, which are network layer design issues, routing algorithms, congestion control algorithms, and references. The body of the document discusses these topics in more detail through several sections. It covers issues like whether the network layer should provide connection-oriented or connectionless service, and compares virtual circuit and datagram networks. It also examines routing algorithms and the optimality principle.
E1 LINK IS EUROPEAN FORMAT ,Europe Line Rate
,E1 LINK, E1 VS T1 LINK, E1 SPECIFICATION, E1 ENCODING tECHNIQUES, high density bipolar , alternate marking inversion,itut,t1,e1 frame format
Slide 02 - Asynchronous Transfer Mode (ATM).pdfKingsleyTettey
This document provides an overview of Asynchronous Transfer Mode (ATM). It discusses how ATM was developed to allow telephone networks to carry different types of traffic beyond just voice calls. The key aspects of ATM covered include its cell-based format and connection-oriented design. Quality of service is handled through permanent and switched virtual connections. While ATM provided capabilities for multimedia networking, its complexity and costs prevented it from widespread adoption compared to other technologies.
This document provides an introduction to the IEEE 802.11 wireless LAN standard. It outlines the standard's architecture including components like stations, basic service sets, extended service sets, and access points. It describes the medium access control sublayer which uses distributed coordination function and point coordination function to provide reliable data delivery and fair medium sharing. It also briefly discusses the physical layer and typical wireless LAN products.
This ppt contains information about concepts of wireless communication, signal propagation effects, spread spectrum, cellular systems, multiple access systems.
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, the key components and functioning of IPv4 including packet structure, fragmentation, and checksum calculation. It then covers the advantages of IPv6 over IPv4 and the differences in packet format and extension headers between the two protocols. Finally, it discusses the challenges of transitioning from IPv4 to IPv6 and different transition strategies like running both protocols simultaneously, tunneling, and header translation.
Global System for Mobile (GSM) is a second generation cellular standard developed for voice services and data delivery using digital modulation. It has a network subsystem including components like the MSC, HLR, VLR, and AuC that handle call processing and subscriber information. The radio subsystem consists of BSCs controlling multiple BTSs to manage radio network access. GSM provides international roaming, high quality voice calls, and supports data services like SMS and fax in addition to voice.
Packet-switched networks (PSNs) allow customers to share network facilities, reducing costs. PSNs use virtual circuits to allow remote sites to maintain multiple connections over a single interface. X.25 was an early packet switching technology that defined the connection between terminals and PSNs. It provided reliability through error checking at the data link and network layers. X.25 addresses remote devices using X.121 addresses and establishes permanent or switched virtual circuits to transmit data between them.
The document discusses different types of transmission media used to transmit signals from sender to receiver. It describes guided media like twisted-pair cable, coaxial cable and fiber-optic cable. It provides details on their characteristics, applications, advantages and disadvantages. Twisted-pair cable is commonly used for telephone lines and low-speed LANs. Coaxial cable has higher bandwidth but is more expensive over long distances. Fiber-optic cable has the highest bandwidth and data rates but requires more skilled installation and maintenance.
A switched network consists of interconnected nodes called switches that can temporarily connect devices linked to the switch. There are three main types of switching: circuit switching, datagram/packet switching, and virtual circuit switching. Circuit switching requires resource reservation and dedicates resources for the duration of a connection. Datagram switching does not reserve resources and allocates them on demand. Virtual circuit switching has aspects of both by dedicating resources only for packets belonging to the same connection. Switches can be constructed in single-stage or multistage designs, with multistage switches using fewer crosspoints.
The document discusses various technologies used for data transmission over telephone and cable networks, including:
1. Telephone networks originally used analog circuit switching to transmit voice calls but have transitioned to separate digital data transfer and signaling networks.
2. Traditional telephone lines support dial-up modems using modulation/demodulation to transmit data within the 3000Hz bandwidth for voice calls.
3. Digital Subscriber Line (DSL) technologies like ADSL provide higher bandwidth internet over existing telephone lines by using frequencies up to 1.1MHz.
4. Cable networks originally provided unidirectional video but now support bidirectional high-speed internet using technologies like DOCSIS to share bandwidth over coaxial and fiber-opt
Optical Fiber Cables :- An Introduction Pradeep Singh
This document discusses fiber optic cables and their components. It begins by classifying optical fibers into single-mode fibers, which carry light along a single path, and multi-mode fibers, which carry multiple light paths. It then describes the core, cladding and coating layers that make up an optical fiber. Total internal reflection is discussed as the mechanism that keeps light confined in the fiber. Common fiber optic components like connectors, couplers and circulators are also outlined.
Frame relay is a packet-switching telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints in wide area networks (WANs). The service, once widely available and implemented, is in the process of being discontinued by major Internet service providers. Sprint ended its frame relay service in 2007, while Verizon said it plans to phase out the service in 2015. AT&T stopped offering frame relay in 2012 but said it would support existing customers until 2016.
This document discusses different types of transmission media used for computer communications, including bounded and unbounded media. Bounded media, such as coaxial cable, twisted pair cable, and fiber optic cable, confine signals to a narrow path. Coaxial cable uses a central copper conductor surrounded by insulation and an outer copper shield. Twisted pair cable consists of pairs of copper wires twisted together. Fiber optic cable uses glass strands to transmit data via pulses of light. Unbounded media, also called wireless media, do not use physical connectors and can include radio waves, microwaves, and infrared waves for transmission.
H.323 is a standard for multimedia communications over packet-based networks. It defines protocols for real-time audio, video and data communications between endpoints such as terminals, gateways and multipoint control units. As an umbrella standard, H.323 references other protocols for functions like call signaling, bandwidth negotiation and transmission of audio and video data. H.323 provides scalable and flexible multimedia communication capabilities and has been widely adopted for voice and video conferencing over both internet and private networks.
A router determines the best route for packets to travel between different networks, allowing communication between subnets, LANs, and WANs. It maintains a table of available routes and uses LAN and WAN interfaces to connect networks. There are various types including broadband, wireless, core, and edge routers, and routers contain external components like antennas and internal components that process and route packets.
Transmission media (data communication)Pritom Chaki
Transmission media is the material pathway that connects computers, different kinds of devices and people on a network. It can be compared to a superhighway carrying lots of information. Transmission media uses cables or electromagnetic signals to transmit data.
This document discusses the OSI model, which defines 7 layers of network communication. It defines each layer, their functions, and the encapsulation process between layers. Key points covered include defining the 7 layers and their functions, comparing TCP and UDP protocols, and stating that OSI model allows different hardware/software to communicate by organizing networks into well-defined modules. The purpose of OSI is to represent a perfect network and organize it into functional layers to allow troubleshooting and different technologies to work together across networks.
Distance vector routing works by having each node maintain a routing table with the minimum distance to reach every other node. Nodes share their routing tables with immediate neighbors periodically or when changes occur, allowing each node to learn optimal routes throughout the network. Each node sends only the minimum distance and next hop information to neighbors, who update their own tables. This sharing of routing information allows all nodes to gradually learn the least-cost routes.
This document describes slides for a chapter on the transport layer. It states that the slides can be freely used and modified for educational purposes with proper attribution. It asks users to mention the source if the slides are used for a class and to note any adaptation if slides are posted online. The document also provides copyright information for the material.
This document provides an overview of various topics related to the network layer, including IPv4, IPv6, ARP, RARP, mobile IP, routing algorithms, and routing protocols. It begins with basics of IPv4 such as its addressing scheme and role in interconnecting networks. IPv6 is then introduced, along with reasons for its development and key features like its large 128-bit addresses. Address Resolution Protocol (ARP) and Reverse ARP (RARP) are also covered. The document concludes by discussing routing algorithms like link-state and distance-vector, as well as protocols including RIP, OSPF, and BGP.
This document discusses different types of transmission media used to transmit signals and data in communication networks. It describes guided media such as twisted pair cable, coaxial cable, and fiber optic cable, which provide a physical path for signal propagation. It also covers unguided or wireless media that transmit signals through air using radio waves, microwaves, or infrared. The key characteristics, applications, and performance of each transmission medium are outlined.
The document discusses the design and implementation process in software engineering. It covers topics like using the Unified Modeling Language (UML) for object-oriented design, design patterns, and implementation issues. It then discusses the design process, including identifying system contexts and interactions, architectural design, identifying object classes, and creating design models like subsystem, sequence, and state diagrams. The example of designing a weather station system is used to illustrate these design concepts and activities.
This document discusses different types of intelligent agents and their environments. It defines rational agents as those that do the right thing given their percepts and goals. The document outlines different types of agent architectures, including simple reflex agents, model-based reflex agents, goal-based agents, and utility-based agents. It also discusses properties of task environments and examples of different environments. Learning agents are introduced as agents that can improve their performance over time through experience.
This document provides an introduction to the IEEE 802.11 wireless LAN standard. It outlines the standard's architecture including components like stations, basic service sets, extended service sets, and access points. It describes the medium access control sublayer which uses distributed coordination function and point coordination function to provide reliable data delivery and fair medium sharing. It also briefly discusses the physical layer and typical wireless LAN products.
This ppt contains information about concepts of wireless communication, signal propagation effects, spread spectrum, cellular systems, multiple access systems.
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, the key components and functioning of IPv4 including packet structure, fragmentation, and checksum calculation. It then covers the advantages of IPv6 over IPv4 and the differences in packet format and extension headers between the two protocols. Finally, it discusses the challenges of transitioning from IPv4 to IPv6 and different transition strategies like running both protocols simultaneously, tunneling, and header translation.
Global System for Mobile (GSM) is a second generation cellular standard developed for voice services and data delivery using digital modulation. It has a network subsystem including components like the MSC, HLR, VLR, and AuC that handle call processing and subscriber information. The radio subsystem consists of BSCs controlling multiple BTSs to manage radio network access. GSM provides international roaming, high quality voice calls, and supports data services like SMS and fax in addition to voice.
Packet-switched networks (PSNs) allow customers to share network facilities, reducing costs. PSNs use virtual circuits to allow remote sites to maintain multiple connections over a single interface. X.25 was an early packet switching technology that defined the connection between terminals and PSNs. It provided reliability through error checking at the data link and network layers. X.25 addresses remote devices using X.121 addresses and establishes permanent or switched virtual circuits to transmit data between them.
The document discusses different types of transmission media used to transmit signals from sender to receiver. It describes guided media like twisted-pair cable, coaxial cable and fiber-optic cable. It provides details on their characteristics, applications, advantages and disadvantages. Twisted-pair cable is commonly used for telephone lines and low-speed LANs. Coaxial cable has higher bandwidth but is more expensive over long distances. Fiber-optic cable has the highest bandwidth and data rates but requires more skilled installation and maintenance.
A switched network consists of interconnected nodes called switches that can temporarily connect devices linked to the switch. There are three main types of switching: circuit switching, datagram/packet switching, and virtual circuit switching. Circuit switching requires resource reservation and dedicates resources for the duration of a connection. Datagram switching does not reserve resources and allocates them on demand. Virtual circuit switching has aspects of both by dedicating resources only for packets belonging to the same connection. Switches can be constructed in single-stage or multistage designs, with multistage switches using fewer crosspoints.
The document discusses various technologies used for data transmission over telephone and cable networks, including:
1. Telephone networks originally used analog circuit switching to transmit voice calls but have transitioned to separate digital data transfer and signaling networks.
2. Traditional telephone lines support dial-up modems using modulation/demodulation to transmit data within the 3000Hz bandwidth for voice calls.
3. Digital Subscriber Line (DSL) technologies like ADSL provide higher bandwidth internet over existing telephone lines by using frequencies up to 1.1MHz.
4. Cable networks originally provided unidirectional video but now support bidirectional high-speed internet using technologies like DOCSIS to share bandwidth over coaxial and fiber-opt
Optical Fiber Cables :- An Introduction Pradeep Singh
This document discusses fiber optic cables and their components. It begins by classifying optical fibers into single-mode fibers, which carry light along a single path, and multi-mode fibers, which carry multiple light paths. It then describes the core, cladding and coating layers that make up an optical fiber. Total internal reflection is discussed as the mechanism that keeps light confined in the fiber. Common fiber optic components like connectors, couplers and circulators are also outlined.
Frame relay is a packet-switching telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints in wide area networks (WANs). The service, once widely available and implemented, is in the process of being discontinued by major Internet service providers. Sprint ended its frame relay service in 2007, while Verizon said it plans to phase out the service in 2015. AT&T stopped offering frame relay in 2012 but said it would support existing customers until 2016.
This document discusses different types of transmission media used for computer communications, including bounded and unbounded media. Bounded media, such as coaxial cable, twisted pair cable, and fiber optic cable, confine signals to a narrow path. Coaxial cable uses a central copper conductor surrounded by insulation and an outer copper shield. Twisted pair cable consists of pairs of copper wires twisted together. Fiber optic cable uses glass strands to transmit data via pulses of light. Unbounded media, also called wireless media, do not use physical connectors and can include radio waves, microwaves, and infrared waves for transmission.
H.323 is a standard for multimedia communications over packet-based networks. It defines protocols for real-time audio, video and data communications between endpoints such as terminals, gateways and multipoint control units. As an umbrella standard, H.323 references other protocols for functions like call signaling, bandwidth negotiation and transmission of audio and video data. H.323 provides scalable and flexible multimedia communication capabilities and has been widely adopted for voice and video conferencing over both internet and private networks.
A router determines the best route for packets to travel between different networks, allowing communication between subnets, LANs, and WANs. It maintains a table of available routes and uses LAN and WAN interfaces to connect networks. There are various types including broadband, wireless, core, and edge routers, and routers contain external components like antennas and internal components that process and route packets.
Transmission media (data communication)Pritom Chaki
Transmission media is the material pathway that connects computers, different kinds of devices and people on a network. It can be compared to a superhighway carrying lots of information. Transmission media uses cables or electromagnetic signals to transmit data.
This document discusses the OSI model, which defines 7 layers of network communication. It defines each layer, their functions, and the encapsulation process between layers. Key points covered include defining the 7 layers and their functions, comparing TCP and UDP protocols, and stating that OSI model allows different hardware/software to communicate by organizing networks into well-defined modules. The purpose of OSI is to represent a perfect network and organize it into functional layers to allow troubleshooting and different technologies to work together across networks.
Distance vector routing works by having each node maintain a routing table with the minimum distance to reach every other node. Nodes share their routing tables with immediate neighbors periodically or when changes occur, allowing each node to learn optimal routes throughout the network. Each node sends only the minimum distance and next hop information to neighbors, who update their own tables. This sharing of routing information allows all nodes to gradually learn the least-cost routes.
This document describes slides for a chapter on the transport layer. It states that the slides can be freely used and modified for educational purposes with proper attribution. It asks users to mention the source if the slides are used for a class and to note any adaptation if slides are posted online. The document also provides copyright information for the material.
This document provides an overview of various topics related to the network layer, including IPv4, IPv6, ARP, RARP, mobile IP, routing algorithms, and routing protocols. It begins with basics of IPv4 such as its addressing scheme and role in interconnecting networks. IPv6 is then introduced, along with reasons for its development and key features like its large 128-bit addresses. Address Resolution Protocol (ARP) and Reverse ARP (RARP) are also covered. The document concludes by discussing routing algorithms like link-state and distance-vector, as well as protocols including RIP, OSPF, and BGP.
This document discusses different types of transmission media used to transmit signals and data in communication networks. It describes guided media such as twisted pair cable, coaxial cable, and fiber optic cable, which provide a physical path for signal propagation. It also covers unguided or wireless media that transmit signals through air using radio waves, microwaves, or infrared. The key characteristics, applications, and performance of each transmission medium are outlined.
The document discusses the design and implementation process in software engineering. It covers topics like using the Unified Modeling Language (UML) for object-oriented design, design patterns, and implementation issues. It then discusses the design process, including identifying system contexts and interactions, architectural design, identifying object classes, and creating design models like subsystem, sequence, and state diagrams. The example of designing a weather station system is used to illustrate these design concepts and activities.
This document discusses different types of intelligent agents and their environments. It defines rational agents as those that do the right thing given their percepts and goals. The document outlines different types of agent architectures, including simple reflex agents, model-based reflex agents, goal-based agents, and utility-based agents. It also discusses properties of task environments and examples of different environments. Learning agents are introduced as agents that can improve their performance over time through experience.
Ian Sommerville, Software Engineering, 9th EditionCh 8Mohammed Romi
The document discusses different types of software testing including unit testing, component testing, and system testing. Unit testing involves testing individual program components in isolation through techniques like partition testing and guideline-based testing. Component testing focuses on testing interactions between components through their interfaces. System testing integrates components to test their interactions and check for emergent behaviors that are not explicitly defined. The document also covers test-driven development, which involves writing tests before code in incremental cycles.
The document provides an overview of software testing. It discusses different types of testing like development testing, test-driven development, release testing, and user testing. It describes unit testing, component testing, system testing, and the goals of validation and defect testing. It also covers topics like the testing process, automated testing, equivalence partitioning, regression testing, and test-driven development.
The document discusses IPv4 addressing and logical addressing in computer networks. It covers the following key points:
- IPv4 addresses are 32-bit addresses that uniquely identify devices connected to the internet. The total address space is 232 or approximately 4.3 billion addresses.
- Addresses can be written in binary or dotted-decimal notation. IPv4 addresses are divided into classes based on the first bits of the address.
- Classful addressing wasted a large portion of addresses. It was replaced by classless addressing which allocates address blocks of variable sizes.
- In classless addressing, a block of addresses is defined as the network address, subnet mask, and number of hosts. The first and last
The document discusses different techniques for weighting terms in the vector space model for information retrieval, including:
- Sublinear tf scaling using the logarithm of term frequency
- Tf-idf weighting
- Maximum tf normalization to mitigate higher weights for longer documents
It also discusses evaluating information retrieval systems using test collections with queries, relevant documents, and metrics like precision and recall. Standard test collections include Cranfield, TREC, and CLEF.
The document discusses processing Boolean queries in an information retrieval system using an inverted index. It describes the steps to process a simple conjunctive query by locating terms in the dictionary, retrieving their postings lists, and intersecting the lists. More complex queries involving OR and NOT operators are also processed in a similar way. The document also discusses optimizing query processing by considering the order of accessing postings lists.
Ian Sommerville, Software Engineering, 9th Edition Ch 23Mohammed Romi
The document discusses project planning for software development. It covers topics like software pricing, plan-driven development, project scheduling, and estimation techniques. Project planning involves breaking down work, anticipating problems, and preparing tentative solutions. A project plan is created at the start of a project to communicate the work breakdown and help assess progress. Planning is done at various stages including proposals, project startup, and periodically throughout the project. Factors like requirements, costs, and risks are considered in planning.
The document discusses requirements engineering and summarizes key topics covered in Chapter 4, including:
- Functional and non-functional requirements and how they differ
- The structure and purpose of a software requirements specification document
- Methods for specifying requirements such as using natural language, structured specifications, and tables
- Challenges in writing requirements clearly and avoiding ambiguity or mixing of requirement types
The document summarizes the vector space model for scoring and ranking documents in response to a query in an information retrieval system. It explains that in this model, documents and queries are represented as vectors in a common vector space. The similarity between a document and query vector is measured by calculating the cosine similarity of the two vectors, which scores and ranks documents based on the terms they share with the query. It also describes how the vector space model allows retrieving the top K documents by relevance rather than using a Boolean retrieval model.
Ian Sommerville, Software Engineering, 9th Edition Ch1Mohammed Romi
The document provides an introduction to software engineering concepts. It discusses what software engineering is, the importance of ethics in software development, and introduces three case studies that will be used as examples throughout the book. Specifically:
[1] It defines software engineering as an engineering discipline concerned with all aspects of software production. Professional and ethical practices are important.
[2] It discusses software engineering ethics and introduces the ACM/IEEE code of ethics for software engineers.
[3] It provides an overview of three case studies that will be referenced in later chapters: an insulin pump system, a patient management system, and a weather station system.
The document discusses architectural design in software engineering. It covers topics like architectural design decisions, views, patterns, and application architectures. Architectural design involves identifying major system components and their communications in order to represent the link between specification and design processes. Common architectural patterns discussed include model-view-controller, layered architectures, repositories, client-server, pipes and filters. The document also provides examples of architectures for different types of applications like transaction processing systems and information systems.
1. The document discusses different types of switched networks including circuit-switched, datagram, and virtual circuit networks. It describes the key characteristics of each type.
2. Circuit switching uses dedicated paths between nodes and has three phases: setup, data transfer, and teardown. Datagram networks treat each packet independently and route using destination addresses in packet headers. Virtual circuit networks combine aspects of circuit and datagram switching.
3. The structures of switches used in different networks are examined, including crossbar switches for circuit switching and various designs for packet switches like Banyan networks.
Ian Sommerville, Software Engineering, 9th Edition Ch 4Mohammed Romi
The document discusses requirements engineering and summarizes key topics covered in Chapter 4, including:
- The importance of specifying both functional and non-functional requirements. Non-functional requirements place constraints on system functions and development process.
- The software requirements specification document defines what the system must do and includes both user and system requirements. It should not describe how the system will be implemented.
- Requirements engineering involves eliciting, analyzing, validating and managing requirements throughout the development lifecycle. Precise, complete and consistent requirements are important for development.
Ian Sommerville, Software Engineering, 9th Edition Ch2Mohammed Romi
This document summarizes key aspects of software processes and models. It discusses the basic activities involved in software development like specification, design, implementation, validation and evolution. It describes process models like waterfall, incremental development and reuse-oriented processes. The waterfall model involves sequential phases while incremental development interleaves activities. Validation includes testing stages from unit to system level. The document also covers designing for change and evolution.
This document provides an overview of Internet Protocol version 4 (IPv4) and version 6 (IPv6). It discusses the need for a network layer in an internetwork, the key components and functioning of IPv4 including packet structure, fragmentation, and checksum calculation. It then covers the advantages of IPv6 over IPv4 and the differences in packet format and extension headers between the two protocols. Finally, it discusses the challenges of transitioning from IPv4 to IPv6 and different transition strategies like running both protocols simultaneously, tunneling, and header translation.
This document discusses the network layer in computer networking and the Internet Protocol (IP). It covers the need for a network layer, IP version 4 (IPv4), IP version 6 (IPv6), and strategies for transitioning from IPv4 to IPv6. Specifically, it describes IPv4 addressing and packet format, fragmentation, checksum, and options. It also outlines IPv6 addressing and packet headers, advantages over IPv4, and extension headers. Finally, it discusses dual stack, tunneling, and header translation approaches for transitioning between the IP versions.
This document discusses building an inverted index to efficiently support information retrieval on large document collections. It describes tokenizing documents, building a dictionary of normalized terms, and creating postings lists that map each term to the documents it appears in. Inverted indexes allow skipping linear scanning and support flexible queries by indexing term locations. The document also covers calculating precision and recall to measure system effectiveness.
Bab 2 membahas landasan teori rekayasa perangkat lunak dan estimasi biaya pembuatan perangkat lunak. Rekayasa perangkat lunak adalah proses pengembangan perangkat lunak dengan prinsip rekayasa untuk menghasilkan perangkat lunak yang bermanfaat bagi pelanggan dengan biaya yang ekonomis. Metode function point digunakan untuk mengestimasi biaya dan waktu pembuatan perangkat lunak berdasarkan ukuran fungsionalitasnya.
This document provides an overview of an information retrieval course. The course will cover topics related to information retrieval models, techniques, and systems. Students will complete exams, assignments, and a major project to build a search engine using both text-based and semantic retrieval techniques. The document defines key concepts in information retrieval and discusses different types of information retrieval systems and techniques.
This document discusses the network layer of the internet protocol (IP) and transitioning between IPv4 and IPv6. It covers the need for a network layer in connecting networks, describes the core functions of IPv4 including addressing, packet structure, fragmentation, and options. IPv6 is introduced as an updated protocol to address deficiencies in IPv4 for a growing internet. Methods for transitioning between the two versions are also outlined, including running both protocols simultaneously, tunneling IPv6 traffic over IPv4, and translating packet headers. Diagrams and examples throughout help illustrate key concepts.
This document discusses internetworking and the Internet Protocol version 4 (IPv4). It covers key topics such as:
- IPv4 uses datagram packets that are independently routed and can be fragmented. Each packet contains a header with fields for source/destination addresses, protocol type, and more.
- IPv4 provides unreliable, best-effort delivery that must be paired with TCP for reliability. It positions IP as the network layer in the TCP/IP protocol suite.
- The header fields like time-to-live, identification, and flags support functions like limiting packet lifetime, reassembling fragmented packets, and indicating last fragments. Fragmentation allows transmission of packets larger than the MTU.
-
The document discusses network layer protocols, specifically Internet Protocol version 4 (IPv4). It begins by explaining the need for a network layer to enable delivery of data packets across multiple links between networks. The key responsibilities of the network layer are host-to-host delivery and routing packets through routers. It then describes the fields in the IPv4 header such as version, header length, total length, protocol, checksum, source/destination addresses, fragmentation, and time-to-live. Examples are provided to illustrate concepts like fragmentation, checksum calculation, and identifying fragment properties. The network layer protocols that make up the TCP/IP protocol suite are also named.
The document discusses IPv4 and its datagram format. It explains that IPv4 is a best-effort, connectionless protocol that provides no error control or flow control. The datagram format includes a header containing fields like version, header length, total length, protocol, source/destination addresses, and an optional data field. It describes fields related to fragmentation, checksum calculation, and optional header fields like timestamps and routing options.
This document discusses internetworking and connecting networks together. It covers topics related to network layer design issues like store-and-forward packet switching, services provided to the transport layer, and implementation of connectionless and connection-oriented services. Specific protocols discussed include IPv4, IPv6, addressing schemes, network address translation, and the transition from IPv4 to IPv6.
This document discusses Internet Protocol (IP) including:
- IP uses datagrams to transmit data in packets across networks and handles fragmentation and reassembly.
- The IP header contains fields for version, header length, type of service, total length, identification, flags, fragment offset, time to live, protocol, header checksum, source address and destination address.
- IP supports options for functions like record route, strict/loose source routing, and timestamps.
- IP uses checksums to detect errors in packet transmission. The sender calculates the checksum over the packet and it is verified by the receiver.
This document provides an overview of the Internet Protocol version 4 (IPv4). It discusses IPv4 as an unreliable, connectionless datagram protocol and describes the fields in the IPv4 header such as version, header length, services, total length, identification, flags, fragmentation offset, time to live, protocol, checksum, source address, destination address, and options. It also covers IPv4 fragmentation when datagrams are divided into smaller pieces to travel across networks with different maximum transmission unit sizes, and the related fields of identification, flags, and fragmentation offset.
The document discusses network layer protocols and IPv4 specifically. It provides three key points:
1) IPv4 is the main network layer protocol in the Internet that provides "best effort" delivery of packets called datagrams from source to destination through various networks in a connectionless manner.
2) IPv4 packets, or datagrams, contain a header with fields that provide routing information and a payload section for data. The header fields include source and destination addresses, identification information, flags for fragmentation, and more.
3) IPv4 supports fragmentation of large datagrams into smaller pieces to accommodate the size constraints of different networks. The fragmentation process and header fields related to fragmentation are described.
A document about Internet Protocol (IP) is summarized as follows:
- Internet Protocol version 4 (IPv4) is responsible for packetizing, forwarding, and delivering packets at the network layer. It provides "best effort" delivery with no guarantees.
- IPv4 packets can be fragmented into smaller pieces by routers if their size exceeds the Maximum Transmission Unit (MTU) of a link. Fragmentation fields in the IPv4 header are used for this purpose.
- The Address Resolution Protocol (ARP) maps IP addresses to link-layer addresses to allow communication between the network and data-link layers.
The document discusses transport layer protocols UDP and TCP. It provides details on their key differences:
- UDP is a connectionless protocol that does not guarantee delivery or order of packets. It has lower overhead and is faster than TCP.
- TCP is connection-oriented and provides reliable, ordered delivery of packets through acknowledgements and retransmissions. It has higher overhead due to these reliability features.
- Both protocols operate at the transport layer, providing process-to-process communication on top of IP's host-to-host delivery. TCP uses handshaking and flow control to establish and manage connections.
IP is the network layer protocol that provides an unreliable, connectionless, best-effort delivery service for transmitting data packets across networks. It operates by fragmenting large data packets into smaller fragments if needed to meet the maximum transmission unit size of the underlying data link layer. Key fields in the IP header include the identification field to identify fragments of the same packet, the fragment offset field to indicate the position of data in the original packet, and flags to indicate if a packet is a fragment or the last fragment.
This document discusses the network layer in the internet. It covers the internet protocol (IP) which provides connectionless best-effort delivery of packets called internet datagrams. The transmission control protocol (TCP) provides reliable stream service using acknowledgments, while the user datagram protocol (UDP) provides connectionless datagram service. The document then describes the IP version 4 protocol, including the header fields, fragmentation, addressing, and subnetting techniques.
This document provides an overview of the Internet Protocol (IP) including key concepts like the IP datagram format, fragmentation, and options. It discusses the IP datagram header fields including version, header length, type of service, total length, identification, flags, fragment offset, time to live, protocol, header checksum, source address, and destination address. It also covers fragmentation, including the maximum transmission unit, fragmentation flags and offset. Finally, it discusses IP options like record route, timestamp, and source routing and provides examples of using ping and traceroute to test IP functionality.
This document provides information about TCP and UDP protocols. It defines port numbers and how they are used to identify processes. TCP provides connection-oriented and reliable data transmission, while UDP provides connectionless and unreliable datagram transmission. The key differences between TCP and UDP headers are described, including the fields in each header and their purposes. Port numbers, both well-known and ephemeral, are explained. Connection establishment and the TCP encapsulation format are also summarized.
The document summarizes key aspects of the Internet Protocol version 4 (IPv4) including:
- IPv4 provides unreliable, connectionless delivery of packets called internet datagrams between hosts on diverse networks.
- The IPv4 header contains fields for version, header length, type of service, total length, identification, flags, fragment offset, time-to-live, protocol, header checksum, source address, and destination address.
- IPv4 addresses are hierarchical, consisting of a network portion and local host portion, and are divided into classes A, B, and C based on network size.
The document discusses different generations of wired local area network (LAN) technologies, starting with Standard Ethernet. It describes Standard Ethernet's characteristics, including its addressing mechanism, CSMA/CD access method, efficiency of around 39%, and popular implementations using coaxial cable or twisted-pair wiring operating at 10 megabits per second. The document also briefly outlines Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet as evolutions of the original Standard Ethernet specification that increased supported speeds over time.
This document discusses the history and foundations of artificial intelligence. It covers early developments in the 1940s-1950s that led to the birth of AI as a field at the 1956 Dartmouth conference. It describes successes and challenges in the 1960s-1970s, the rise of knowledge-based systems and expert systems in the 1970s, and AI becoming an industry in the 1980s. The return of neural networks in the 1980s-1990s is also summarized. The document outlines different approaches to defining and pursuing AI, including systems that think like humans, think rationally, act like humans, and act rationally. It lists philosophy, mathematics, neuroscience, and other disciplines as foundations of AI.
The document discusses problem-solving agents and uninformed search strategies. It introduces problem-solving agents as goal-based agents that try to find sequences of actions that lead to desirable goal states. It then discusses formulating problems by defining the initial state, actions, goal test, and cost function. Several examples of problems are provided, like the Romania tour problem. Uninformed search strategies like breadth-first search, uniform-cost search, and depth-first search are then introduced as strategies that use only the problem definition, not heuristics. Breadth-first search expands nodes in order of shallowest depth first, while depth-first search expands the deepest node in the frontier first.
This document provides an overview of multiple access protocols for shared wireless media. It discusses random access protocols like ALOHA, slotted ALOHA, CSMA, CSMA/CD, and CSMA/CA. ALOHA protocols allow stations to transmit whenever they have data, which can cause collisions. Slotted ALOHA and CSMA protocols reduce collisions by coordinating transmissions. The document also covers controlled access protocols like reservation, polling, and token passing that establish transmission rights to avoid collisions. It includes frame formats, throughput calculations, and flow diagrams to illustrate how each protocol manages access to the shared channel.
The document discusses the structure of OpenGL programs, including initializing shaders and setting up vertex arrays and buffer objects. Most OpenGL programs have a main function that specifies callbacks, opens a window, and enters an event loop. Initialization functions set up viewing parameters, shaders, and vertex attributes in buffer objects. A display callback renders the vertex data by drawing arrays. The document also covers topics like coordinate systems, the OpenGL camera model, and orthographic viewing.
The document discusses graphics programming and OpenGL. It introduces OpenGL, describing it as a hardware-independent interface consisting of over 700 commands. It outlines the OpenGL API, including primitive functions, attribute functions, and viewing functions. It also covers OpenGL primitives like points, lines, and polygons, as well as attributes like color. It explains orthographic and two-dimensional viewing in OpenGL.
This document summarizes key aspects of software engineering processes and models. It discusses the fundamental activities of software specification, development, validation, and evolution. It describes plan-driven and incremental process models like the waterfall model and incremental development. It also covers topics like software prototyping, reuse-oriented processes, and coping with changing requirements through change avoidance and change tolerance strategies.
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2. 20.2
20-1 INTERNETWORKING
In this section, we discuss internetworking, connecting
networks together to make an internetwork or an
internet.
Need for Network Layer
Internet as a Datagram Network
Internet as a Connectionless Network
Topics discussed in this section:
5. 20.5
Figure 20.3 Network layer at the source, router, and destination
the source is responsible for creating a packet from the data
coming from another protocol (such as a transport layer
protocol or a routing protocol)…Fragmentation.
6. 20.6
Figure 20.3 Network layer at the source, router, and destination
The network layer at the destination is responsible for address
verification; it makes sure that the destination address on the packet is
the same as the address of the host. If the packet is a fragment, the
network layer waits until all fragments have arrived,
7. 20.7
Figure 20.3 Network layer at the source, router, and destination (continued)
responsible for routing the
packet. When a packet arrives,
the router or switch consults
its routing table and finds the
interface from which the
packet must be sent.
8. 20.8
Switching at the network layer in the
Internet uses the datagram approach to
packet switching.
Note
10. 20.10
20-2 IPv4
The Internet Protocol version 4 (IPv4) is the delivery
mechanism used by the TCP/IP protocols.
Datagram
Fragmentation
Checksum
Options
Topics discussed in this section:
13. 20.13
Header length (HLEN). This 4-bit field defines the total
length of the datagram header in 4-byte words. This
field is needed because the length of the header is
variable (between 20 and 60 bytes). When there are no
options, the header length is 20 bytes, and the value of
this field is 5 (5 x 4 = 20). When the option field is at its
maximum size, the value of this field is 15 (15 x 4 = 60).
Header length (HLEN)
18. 20.18
Differentiated Services
In this interpretation, the first 6 bits make up the
codepoint subfield, and the last 2 bits
are not used. The codepoint subfield can be used in
two different ways.
a. When the 3 rightmost bits are Os, the 3 leftmost bits are interpreted the same as
the precedence bits in the service type interpretation-it is compatible with the old
interpretation-
b. When the 3 rightmost bits are not all Os, the 6 bits define 64 services based on the
priority assignment by the Internet or local authorities according to Table 20.3.
20. 20.20
16 bit…The total length field defines the
total length of the datagram including
the header+data.
Note
Length of data =total length - header length
21. 20.21
some physical networks are not able to
encapsulate a datagram of 65,535 bytes
in their frames. The datagram must be
fragmented to be able to pass through
those networks.
Note
22. 20.22
Figure 20.7 Encapsulation of a small datagram in an Ethernet frame
the Ethernet protocol has a minimum and maximum
restriction on the size of data that can be encapsulated in a frame (46 to
1500 bytes).
when a machine decapsulates the datagram, it needs to check the
total length field to determine how much is really data and how
much is padding
23. 20.23
•Identification, flag and Fragmentation offset: This fields
is used in fragmentation.
•Time to live: A datagram has a limited lifetime in its
travel through an internet. The datagram was discarded
when the value became zero.
•Protocol: This 8-bit field defines the higher-level protocol
that uses the services of
the IPv4 layer.
26. 20.26
An IPv4 packet has arrived with the first 8 bits as shown:
01000010
The receiver discards the packet. Why?
Solution
There is an error in this packet. The 4 leftmost bits (0100)
show the version, which is correct. The next 4 bits (0010)
show an invalid header length (2 × 4 = 8). The minimum
number of bytes in the header must be 20. The packet has
been corrupted in transmission.
Example 20.1
27. 20.27
In an IPv4 packet, the value of HLEN is 1000 in binary.
How many bytes of options are being carried by this
packet?
Solution
The HLEN value is 8, which means the total number of
bytes in the header is 8 × 4, or 32 bytes. The first 20 bytes
are the base header, the next 12 bytes are the options.
Example 20.2
28. 20.28
In an IPv4 packet, the value of HLEN is 5, and the value
of the total length field is 0x0028. How many bytes of
data are being carried by this packet?
Solution
The HLEN value is 5, which means the total number of
bytes in the header is 5 × 4, or 20 bytes (no options). The
total length is 40 bytes, which means the packet is
carrying 20 bytes of data (40 − 20).
Example 20.3
Length of data =total length - header length
29. 20.29
An IPv4 packet has arrived with the first few hexadecimal
digits as shown.
0x45000028000100000102 . . .
How many hops can this packet travel before being
dropped? The data belong to what upper-layer protocol?
Solution
To find the time-to-live field, we skip 8 bytes. The time-to-
live field is the ninth byte, which is 01. This means the
packet can travel only one hop. The protocol field is the
next byte (02), which means that the upper-layer protocol
is IGMP.
Example 20.4
30. 20.30
Fragmentation
•A datagram can travel through different networks. Each
router en-de-capsulates the IPv4 datagram from the frame
it receives.
•The format and size of the received frame depend on the
protocol used by the physical network.
•One of the fields defined in the format is the maximum
size of the data field. - the total size of the datagram must
be less than this maximum size-
31. 20.31
Figure 20.9 Maximum transfer unit (MTU)
To make the IPv4 protocol independent of the physical network,
the designers decided to make the maximum length of the IPv4
datagram equal to 65,535 bytes.
33. 20.33
Fragmentation
•When a datagram is fragmented, each fragment has its own header
with most of the fields repeated, but with some changed.
• A Datagram can be fragmented several times before it reaches the
final destination.
•Whereas the fragmented datagram can travel through different
routes.
•All the fragments belonging to the same datagram should finally
arrive at the destination host.
34. 20.34
Fields Related to Fragmentation
Identification:
• 16 bits Uniquely define in all fragments.
•To guarantee uniqueness, the IPv4 protocol uses a counter to
label the datagrams.
•The counter is initialized to a positive number. When the IPv4
protocol sends a datagram, it copies the current value
of the counter to the identification field and increments the
counter by'~ 1.
35. 20.35
Fields Related to Fragmentation
Flags:
• 3-bit field. The first bit is reserved. The second bit is called the
do not-fragment bit.
•If its value is 1, the machine must not fragment the datagram.
•If its value is 0, the datagram can be fragmented if necessary.
•Third bit is called the more fragment bit.
•If its value is 1, it means the datagram is not the last fragment.
•If its value is 0, it means this is the last or only fragment
37. 20.37
Fields Related to Fragmentation
Fragmentation offset.:
13-bit field. shows the relative position of this fragment
with respect to the whole datagram.
Measured in units of 8 bytes. Figure 20.11 shows a
datagram with a data size of 4000 bytes fragmented into
three fragments.
40. 20.40
A packet has arrived with an M bit value of 0. Is this the
first fragment, the last fragment, or a middle fragment?
Do we know if the packet was fragmented?
Solution
If the M bit is 0, it means that there are no more
fragments; the fragment is the last one. However, we
cannot say if the original packet was fragmented or not. A
non-fragmented packet is considered the last fragment.
Example 20.5
41. 20.41
A packet has arrived with an M bit value of 1. Is this the
first fragment, the last fragment, or a middle fragment?
Do we know if the packet was fragmented?
Solution
If the M bit is 1, it means that there is at least one more
fragment. This fragment can be the first one or a middle
one, but not the last one. We don’t know if it is the first
one or a middle one; we need more information (the
value of the fragmentation offset).
Example 20.6
42. 20.42
A packet has arrived with an M bit value of 1 and a
fragmentation offset value of 0. Is this the first fragment,
the last fragment, or a middle fragment?
Solution
Because the M bit is 1, it is either the first fragment or a
middle one. Because the offset value is 0, it is the first
fragment.
Example 20.7
43. 20.43
A packet has arrived in which the offset value is 100.
What is the number of the first byte? Do we know the
number of the last byte?
Solution
To find the number of the first byte, we multiply the offset
value by 8. This means that the first byte number is 800.
We cannot determine the number of the last byte unless
we know the length.
Example 20.8
44. 20.44
A packet has arrived in which the offset value is 100, the
value of HLEN is 5, and the value of the total length field
is 100. What are the numbers of the first byte and the last
byte?
Solution
The first byte number is 100 × 8 = 800. The total length is
100 bytes, and the header length is 20 bytes (5 × 4), which
means that there are 80 bytes in this datagram. If the first
byte number is 800, the last byte number must be 879.
Example 20.9
45. 20.45
Checksum
•Principles. First, the value of the checksum field is set to O.
Then the entire header is divided into 16-bit sections and added
together. The result (sum) is complemented and inserted into the
checksum field.
•The checksum in the IPv4 packet covers only the header, not the
data. There are good reasons for this.
46. 20.46
Figure 20.13 shows an example of a checksum
calculation for an IPv4 header without options. The
header is divided into 16-bit sections. All the sections are
added and the sum is complemented. The result is
inserted in the checksum field.
Example 20.10
48. 20.48
20-3 IPv6
The network layer protocol in the TCP/IP protocol
suite is currently IPv4. Although IPv4 is well designed,
data communication has evolved since the inception of
IPv4 in the 1970s. IPv4 has some deficiencies that
make it unsuitable for the fast-growing Internet.
Advantages
Packet Format
Extension Headers
Topics discussed in this section:
49. 20.49
20-3 IPv6
Disadvantages of IPV4:
•Despite all short-term solutions, such as subnetting,
classless addressing, and NAT,
(address depletion).
•The Internet must accommodate real-time audio and
video transmission.
•The Internet must accommodate real-time encryption
and authentication of data for some applications.
50. 20.50
20-3 IPv6
The format and the
length of the IP address
were changed along
with the packet format.
Related protocols, such
as ICMP,ARP, IGMP
and Routing Protocol.
51. 20.51
20-3 IPv6 advantages over IPv4
1. Large address space.
2. Better Header format.
3. New options to add new functions,
4. IPv6 is designed to allow the extension of the
protocol if required by new technologies or
applications.
5. More Security.
6. Add a mechanism (called-jlow label) has been
added to enable the source to request special
handling of the packet. This mechanism can be
used to support traffic such as real-time audio
and video.
52. 20.52
Figure 20.15 IPv6 datagram header and payload
The length of the base header is fixed at 40 bytes.
54. 20.54
• Version. This 4-bit field defines the version number of the
IP. For IPv6, the value is 6.
• Priority. The 4-bit priority field defines the priority of the
packet with respect to traffic congestion.
• Flow label. The flow label is a 3-byte (24-bit) field that is
designed to provide special handling for a particular flow
of data.
• Next header. The next header is an 8-bit field defining the
header that follows the base header in the datagram. and
protocol fields
56. 20.56
Priority
“The priority field of the IPv6 packet defines the
priority of each packet with respect to other
packets from the same source”
IPv6 divides traffic into two broad categories:
1-congestion-controlled ///2-noncongestion-
controlled.
57. 20.57
Priority
•If a source adapts itself to traffic slowdown when there is
congestion, the traffic is referred to as congestion-
controlled traffic.
•Congestion-controlled data are assigned priorities from 0
to 7, as listed in
Table 20.7.
58. 20.58
Table 20.7 Priorities for congestion-controlled traffic
Example
Process don’t define priority
Background process news is a good example
E-mail service
A protocol that transfers data while the user is
waiting. As ftp.
Protocols such as TELNET that need user
interaction
Routing protocols such as OSPF and RIP and
management protocols such as SNMP
59. 20.59
Priority
•Non-congestion-Controlled Traffic This refers to a type of
traffic that expects minimum delay.
•Discarding of packets is not desirable. Re-transmission in
most cases is impossible. In other words, the source does
not adapt itself to congestion.
-Real-time audio and video are examples-
•Priority numbers from 8 to 15 are assigned to non-
congestion-controlled traffic.
61. 20.61
Flow Label 3-byte
• The combination of the source address and the value of
the flow label uniquely defines a flow of packets for
handling by routers
• Label on router, a flow is a sequence of packets that
share the same characteristics such as traveling the same
path.
• When the router receives a packet, it consults its flow
label table to find the corresponding entry for the flow
label value defined in the packet.
• This can be used in different application as speed up the
processing, Real-time audio or video
64. 20.64
Figure 20.17 Extension header types
used when the source needs
to pass information to all
routers
strict source route and the loose source
route options of IPv4.
The concept of fragmentation is the same
as that in IPv4.
For Network security
that provides confidentiality
and guards against eavesdropping.
The destination option is used when the
source needs to pass information to the
destination only
66. 20.66
20-4 TRANSITION FROM IPv4 TO IPv6
Because of the huge number of systems on the
Internet, the transition from IPv4 to IPv6 cannot
happen suddenly. It takes a considerable amount of
time before every system in the Internet can move from
IPv4 to IPv6. The transition must be smooth to prevent
any problems between IPv4 and IPv6 systems.
Dual Stack
Tunneling
Header Translation
Topics discussed in this section:
68. 20.68
Dual stack
• a station must run IPv4 and IPv6 simultaneously until all
the Internet uses IPv6.
• To determine which version to use when sending a
packet to a destination, the source host queries the DNS.
• If the DNS returns an IPv4 address, the source host
sends an IPv4 packet. If the DNS returns an IPv6
address, the source host sends an IPv6 packet.
70. 20.70
Tunneling strategy
• is a strategy used when two computers using IPv6 want
to communicate with each other and the packet must pass
through a region that uses IPv4.
• To pass through this region, the packet must have an IPv4
address. So the IPv6 packet is encapsulated in an IPv4.
• It seems as if the IPv6 packet goes through a tunnel at
one end and emerges at the other end. To make it clear
that the IPv4 packet is carrying an IPv6 packet as data,
the protocol value is set to 41.
72. 20.72
Header translation strategy
• Header translation is necessary when the majority of
the Internet has moved to IPv6 but some systems still
use IPv4.
• The sender wants to use IPv6, but the receiver does not
understand IPv6.
• Tunneling does not work in this situation because the
packet must be in the IPv4 format to be understood by
the receiver.
• In this case, the header format must be totally changed
through header translation.